Retractable landing gear



June 18, M. c. BAUMANN RETRACTABLE LANDING GEARv Filed Aug. 30, 1920 3 Shasta-Sheet .l

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W flare A June 18, 1929. M. c. BAUMANN RETRACTABLE LANDING GEAR Filed Aug. 30, 1920 t June 18, 1929. M. c. BAUMANN RETRACTABLE LANDING GEAR Filed Aug. 50. 1920 3 Sheets-$heet llj ' Patented June 18, 1929. i I I v UNITED STATES PATENT" oFFicE.

I 'mit'roii c. AUl flANN oF DAYTON, OHIO.

RETRACTABLE LANDING GEAR.

Application filed August 30, 1920. Serial No. 406,763.

The present invention relates to airplanes This rod 32 forms a sliding joint at its up- .55 and particularly to landing gear therefor. per end in a sleeve 80, which sleeve is provid- Among the objects ofthe invention is to ed with down turned forks 34 for the purpose render more efiicient the action ofthe landof retaining elastic cord 35 which operates ing-gear while in extended position and to under these forks and over the end of rod more effectively decrease the airresistance 32, the latter being also provided with a fork 60 of landing gear parts when in the retracted for the purpose of retaining the elastic cord position. in place. This latter fork is indicated at 36.

Other objects and advantages of the present This sleeve 80 forms one member of theinvention will appear from the following deg swivel joint 37, the other member of which is In the drawings:

scription, referencebeing had to the accomin the form of an internally threaded sleeve 65 panying drawings, wherein a preferred form 38 adapted to coact with the retracting of, embodiment of the present invention is worm 39. j v clearly shown. A. This retracting worm is journalled at its lower end in a bearing supported in a stirrup Fig. 1 is a more or less diagrammatic view 40 attached to plate 22, whichplate is, as 7 of one-half of the landing gear forming the above mentioned, fastened to bulkhead 21. subject of the present application. Figs. 4 and 5 clearly illustrate the method Fig. 1% is a similar view of such landing of mounting plate 22 on bulkhead 21.

gear showing the parts in the flight position. The upper end of this worirr 39 is jour- Fig. 2 is aview of one-half of the gearbox nalled in a suitable gear box 23 and is pro- 7 with the retracting worms and the worm vided with antifriction bearings and a worm gears in a position there1n.- a gear coact ng with a worm gear 51 which Fig. 3 is a side view of the gear box with 13 provided with a suitable spindle extending 25 the pinion of. the driving gear extending outside of the gear box and attached through therefrom and also showing the universal universal joint to rod 61 extending to the joint connection with the operating shaft. instrument board of the plane and provided Fig. 4 is a detail of the anchor plate for the at its end with the crank 62 as indicated diabottom of the retracting worm. grammaticallyin Figs. 9 and 10. 30 Fig. 5 is a side view of the same plate show- It will be noted that the worm shaft 39 is ing its attachment to the bulkhead. mounted at its upper end with an antifric- Fig. 6 is a view partly in section of the tion thrust bearing and at its lower end in a swivel and its attachmentto the spindle carplain bearing. The purpose of this method rying rod. of mounting is as follows:

Fig. 7 "is an elevation of the swivel, viewed When the wheels are being lifted by means from the right of; Fig. 6. f I of the operating crank or motor, the thrust Fig 8 is a'detail of the spindle carry ng is taken by the upper bearing and an antirod with the "wheel removed. friction bearing is provided to render this Figs.9andlOarediagramnmtic views showoperation more easily performed. On the 40 ing the relative position of the several parts other hand, when the wheels are in landing of the landing gear when in flight and landposition, the upward-thrust of the wheels is ing positions respectively. taken by the lower plain bearing and there In Fig. 1 the outer shell of thefuselage is is suflicient friction/in this bearingto prevent indicated 20 as being formed upon-a bulkhead the worm shaft 39 from revolving and allow- 21. 'Attached to bulkhead 21 by means of ing the fuselage to come in contact with the plates 22, 24tand gear box23 and provided ground'eircuits. This arrangement is obviwith suitable bearings therein, are the movously desirable when the pitch of the thread ing parts of the landing gear. on shaft 39 is considered. In order to make The landing gear proper consists of the the operation of retracting the wheels rapid,

5 wheel 30 mounted upon a spindle 31, attached the pitch of the thread on shaft 39 will j ecesrigidly to the lower end of a tube or rod 32 sarily be rather high. This tends to increase by means of'a forging or casting 33, the spinthe reversibility of the thread and this form dle. forging, and rod thus forming a single of mounting the shaft was devised to overrigid piece. come this difliculty;

It will be understood that while in the description, as mentioned, only one of these worms 39 has'rod member 32 with wheel 30, these parts are duplicated for the other side of the plane.

Figs. 9 and 10 illustrate very clearly the operation of the device, Fig. 9 showing the wheels in flight position and Fig. 10 illustrating the position of the gear at the time of landing.

It is thought that the further description of the operation of the device is unnecessary in view of the detailed description above, and the showing in the drawings.

In Figs. 1, 1*, 9 and 10 there is illustrated only one folding bracerod 70, but it should be understood that there are two or more of these usually, in order to take longitudinal shocks upon the wheel 30 when the machine is travelling along the surface,

It will be readily seen that by the present device substantially all of the air resistance. of the landing gear during the flightof the airplane has been eliminated, as the rod and brace members are withdrawn entirely within the fuselage While the wheels in retracted position occupy the position indicated in Fig. 1, effectively closing the pocket or hole pro vided for them and having only a small porf tionthereto extending into the airstream r It will beunderstoodxtliat suitable slots will be provided for the passage through the lower portion of the fuselage of all of the I .rodsor folding brace members 70,

7 gear may be raised or lowered as the operator It should be noted that while the device is described and shown as a hand operative mechanism, it is contemplated that it may be power operated= In order to accomplish this result it would be suficient to mount upon the plane in the aircurrents, a small air operated motor and convey (thepower. thus produced to the operating shaft 61 through a clutch mechanism of some sort and such mechanism may even be provided with reverse mechanism in orderthat the landing desires while the plane is in flight. Vvhile the motor of this sort is suggested, nevertheless, it is obvious that any other suitable form of motor might be substituted therefor without departing'from the invention.

While the form of mechanism herein shown and described, constitutes a preferred form of embodiment of the present invention, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow. v

VVhatI claim is as follows:

' 1. A retractable landing gear for airplanes,

comprising wheels mounted uponspindles; rigidly secured to upright members, shock absorbing fmeans upon the upper end of said members and movable therewith to different positions of adjustment, means operating to lift the upright members with the attached misuse spindles and wheels into the fuselage of the airplane.

2. A retractable landin gear comprising a retracting worm, a threaded sleeve upon the worm, a substantially rigid member having reciprocatory movement with the sleeve and carrying at its lower end a landing wheel, shock absorbing connection between said member and the sleeve, and means for rotating the worm.

3. A retractable landinggear for airplanes including a wheelimounted upon a spindle carried by an upright strut member, an adjusting screw for reciprocating the strut member into and out of the fuselage of an airplane and a laterally extendin brace member pivoted at one end-to the uselalge and at its other end to the wheel carrying structure for guiding the wheel and bracing it in extended landing position.

4. In an airplane, a substantiallycircular opening in the fuselage, a retractable landing gear including a wheel movable laterally into said opening-means for retracting the landing gear and (fausing thewheel to substantially fill the opening, wherebyvthe lateral face of the wheel will substantially, coincide with the surface of the fuselageof the aeroplane, c T

5. Inretr'actable landing 1 gear for airplanes an upright reciprocating supporting member, a landing wheel mounted at the lower end of said reciprocatory supporting member andmovable therewith, means for retracting the reciprocatory supporting member in a substantially vertically disposed path of travel and shock absorbing means against the tension of whichthe upright supporting member is capable of reciprocatory movement at any point in its range of adjustment. 6. In an airplane, a rotatable drive shaft, a worm shaft, means for transmitting motion from the drive shaft to the worm shaft, a threaded sleeve mounted upon the worm shaft, a wheel carrying supporting member yieldingly attached to the sleeve for reciprocatory movement in unison therewith, whereby when the worm shaft is rotated the wheel carrying supporting member is extended 0r retracted through a substantially vertical reciprocatory movement and capable of limited movement' independent thereof to compensate for shock, by the resiliency of its yielding attachment to the sleeve. I I 7. In an airplane, a retractable landing gear comprising land wheels, circular pockets in the fuselage, means for withdrawing the landing gear to cause the wheels to enter latmitting motion in relation with the fuselage connections, means for retracting the pivotal.

connections of said struts in substantially straight paths of travel and simultaneously oscillating the struts transversely to the line of flight about their pivotal connections, to lift the wheels and supporting struts into the fuselage.

10. The combination with an aeroplane, a fuselage, retractable'alighting means, operating means therefor, by which the alighting means may be retracted, and means for transfrom said operatingmeans to actuate the alighting means, said alighting means being operable in various intermediate positions thruout its range of movement, and shock absorbing-means within the fuselage operable to compensate for shock to said alighting means in any position to which it may be adjusted.

11. In a folding landing gear for airplanes a pair of frames adjustable vertically and i laterally into outspread relation beyond the limits of the airplane fuselage, a carrying wheel mounted on each frame, substantially vertically disposed threaded shafts, internal 1y threaded sleeves upon said shafts and ad justable axially upon the shafts by the rotation of the .latter, said wheel carrying frames being pi'votally connected with saidsleeves,'means for rotating the shafts to retract and extend the wheel carrying frames, and brace bars pivoted to the fuselage structure movable outwardly and downwardly in a plane transverse to the line of flight for supporting the wheel carrying frames when in extended position.

12. A retractable landing gear, comprising a retracting worm, a threaded sleeve upon the worm, a normally substantially upright, weight supporting member carrying at its lower end 'a landing wheel, the upper end being connected'with the sleeve for reciprocatory movement thereby means for guiding the lower end of the wheel carrying member outwardly in a lateral direction transverse to the line of flight during its descending movement, by which the wheel will be spaced laterally away from thefuselage, .and the. carrying member will afford a. lateral brac- L ing effect, and for retracting 'the wheel inwardly towardthe fuselage during the as-' cending .movement of the wheel carrying member, and means for rotating the worm.

13. A retractable landing gear for air planes including a reciprocatory strut, a

wheel carried by said strut, adjusting means for reciprocating the strut to extend and retract the wheel and a yielding coupling interposed between the .wheel carrying strut of flight, and a link havingone end pivoted to a stationary support, the other end connected to said supporting member and controlling the swinging movement of the support in unison with its reciprocation.

15.- In a retractable landing gear for aeroplanes, a retractable main weight supporting member, one end 0 which movesin a substantially vertical straight line the other .end of which moves in an arcuate path of travel transversely to the line of flight, and means to actuate said retractable member into and out of operative position.

16. In a folding landing gear for airplanes, a pair of normally substantially upright, main weight supporting struts, a reciprocatory carrier to which each strut is pivoted, on an axis extending longitudinally of the fuselage, threaded shafts operatively connected with the reciprocatory carriers, means to rotate'the threaded shafts to retractthe carriers upward, and guide links connected with the supporting struts effecting a swinging movement of the struts on their pivotal axes in directions transverse to the longitudinal extent of the fuselage in unison with their reciprocatory movement and adapted to brace the struts when extended.

17. In a folding landing gear for airplanes,

a pair of normally substantially upright,

main weight supportingstruts, reciprocatory supporting means for the struts movable in a substantially straight line to which the struts are pivoted .on axes disposed longitudinally in relation with the fuselage, means for reciprocating the carrier, means to draw the struts upward, and guide links pivoted to the fuselage'and connected with the supporting struts effecting a swinging movement of the struts transversely in relation with the fuselagein unison with their reciprocatory movement and bracing the struts when .extended. 18. In a retractable landing gear for airplanes, an upright reciprocatory main weight supporting. member having a pivotal connection at its upper end movable u ward and downward in a substantial straight line, a landing wheel carried at the lower end of the supporting member, means for retracting the supporting member upwardly and means for oscillating the supporting member about its pivotal connection in a planeangular-to that of the wheel during its reciproeatory movement. l p 19. A retractable landing gear forairplanes including a wheel, a pair of angularly disposed interpivoted strut members-movable in a plane transversely of the line of flight, by

which the Wheel is carried, adjusting means .for varying the angular relation of the strut imembers to extend and retract said wheel, and I resilient means against the yielding resistance of which one of the strut members is longitudi-' nally movable independent of the adjusting means. Y l J 20. A retractable landing gear for airplanes including a wheel, a pair of angularly disposed interpivoted struts arranged transs versely of the airplane fuselage, by which the wheel is carried in juxtaposition t their interpivotal point, fromwhich point one of the arms extends upwardly and the other armlaterally when the wheel is extended, the lat: erally'extending arm having a stationary pivotal connection in spaced relation with the interpivotal point of said struts, the upward extending strut having a lineally adjustable pivotal connection also in spaced relation with the interpivotal connection of the struts, and

means for lineally adjustingthe last men-s tioned pivotal connection to effect the extension and retraction of said wheel.

21. In an aeroplane, a retractable landing gear, disc wheels carried thereby, a fuselage having lateral openings therein, and means, for retracting the landing gear to cause said disc wheels to form closure lids for said fuselage openings. I

. '22., In a retractable landing gear for airplanes, a carrying wheel, an adjustable supiporting structure by which the Wheel is carried, means for adjusting the supporting structure to extend and retract the wheel relative tothe fuselage, and thrust operated means 7 set by the impact of the wheel in landing for resisting the retractive movement of the adustable supportmg structure.

23. In combination with an aeroplane, re-

tractable alighting means, operating means therefor, means for transmitting motion from said operating means to the ahghtmg means,

and thrust controlled means operative by the alighting meansunder the influence of such landing impact from the position to which the alighting means may have been extended.

25. In combination with an aeroplane, re-

tractable alighting means including normally substantially upright, main weight supporting struts having at one end substantially vertical reeiprocatory movement in a straight line and lateral swinging movementat the opposite end into and out of operative position, operating means therefor and means for transnnttmg motion from the operating means to actuate said ahghtmg means, and

brace means for said alighting means movable therewlth.

= 26. A retractablelanding chassis forairplanes, a threaded adjusting shaft therefor and a nut co-acting therewith, the pitch of the screw and nut being such that the chassis will travel under influence of gravity to ops erative landing position, and thrust controlled means for resisting reverse movement of the screw under influence of the landing impact.

27. A retractable landing gear for airplanes, an adjusting screw therefor having an elongated thread pitch, the pressure angle oil which is insufficient to resist the axial pressure of the landing gearand a nut co-acting therewith, permitting the landing gear to opcrate the screw idly during the movement of the landing gear into extended position, and means for actuating said screw to retract the landing gear.

28. A retractable landing gear for airplanes, a threaded adjusting shaft and meeting nut therefor, the value of the tangent of the angle of the shaft. thread being less than the coe'llicient of friction between the thread and enacting nut whereby the shaft will not tive movement-of the shaftv and nut in one direction and means tending to resist the relative rotation of the nut and-screw in the opposite direction to resist return movement of the landing gear under the influence of the landing thrust.

' 294A retractable landing gear for airplanes including a substantially vertically adjustable normally upright, main weight supporting struts. a threaded adjusting shaft and coacting nut therefor for vertically retracting and extending said supporting struts and sustaining the landing thrust, and means controlled by" the thrust for retarding relative movement of the nutand shaft, and means for relatively actuating the nut and shaft to adjust the landing gear,"

30. A retractable landing gear fQr airplanes, a threaded adjusting shaft and'co- III) 7 to temporarily lock the shaft and nut against relative adjustment.

31. A retractable landing gear for air:

planes, a threaded adjusting shaft and counting nut therefor, a thrust bearing, tending to resist relative adjustment of the nut and shaft to eflcct adjustment of the landing gear in one direction and permitting free relative rotation of the shaft and nutto adjust the landing gear in the opposite direction.

32. A retractable landing gear for airplanes, a threaded adjusting shaft'and coacting nut therefor, an anti-friction thrust hearing and a frictional thrust bearing-for said shaft opposed one to the other whereb I the landinggcar is freely adjusted in one irection in unison withthe rotation of the shaft, but the retrograde movement of the landing gear is resisted by said'frictional thrust bearing.

33. In a retractable landing gear for airplanes, a rctractable wheel carrying member,

planes including a wheel, a pair of angularly.

disposed interpivoted struts arranged transversely of the airplane fuselage, by which the wheel is'carried in juxtaposition to their-in terpivotal point, from which point one of the arms extends vupwardly and the other arm laterally when thewheel'is extended, the laterally extending arm having a stationary pivotal connection 'in spaced relation with the interpivotal point of said struts, the upwardly extending struthaving a lineally adjustable pivotal connection also in spaced relation with the interpivotal connection of the struts, and an adjusting screw for vertically adjusting the last mentioned pivotal connection to effect the extension and retraction of the wheel,

35. A retractable landing gear for air planes comprising a' substantially vertically disposed retracting worm, a threaded sleeve upon'the worm, a substantially rigid strut member resiliently connected adjacent its upper end with the sleeve for 'reciprocatory movement therewith, means for guiding the lower end of the strut member outwardly in a direction transverse with the linejcf flight simultaneously with its reciprocatory movement and a ground engaging member carried bythelower end of said strut and projected laterally beyond the fuselage of the airplane to afiord a lateral bracing effect simultaneously with its vertical adjustment, and means for actuating the Worm.

-36, The combination with a retractable landing gear for airplanes of a revoluble adjusting screw therefor capable of :1. limited degree of longitudinal movement, and

frictional contact surfaces engaged by the longitudinal shifting movement of the screw under the influence-of landing impact, to

resist rotary motion of the screw, the weight of the landing gear during extension and retraction operating to hold the screw at the opposite limit of its longitudinal movement to maintain said frictional contact surfaces out of engagement with each other.

37. The combination with a retractable landing gear for airplanes of a revoluble adjusting screw therefor capable of limited degree of longitudinal movement, and clutch means for locking the screw against revoluble movement engaged and disengaged by longitudinal movement of the screw, the weight of the landing gear serving to shift the screw to unlock the clutch. means, and the thrust impact of thegcar 1n landing serving to shift the screw to engage the clutch means.

- 38. The combination. with a retractable landing gear for airplanes, of adjusting means therefor permitting the landing gear a limited degree of lost motion, and locking means for said landing gear to maintain the gear in adjusted position controlled by said lost= motion, whereby the locking means is released by the movement in one direction incident to the weight of the landing gear and is locked by the movement in the opposite direction incident to'the impact gear in landing.

=39. The combination. with a retractile landing gear for airplanes, of a revoluble adjusting screw therefor, and pressure controlled retarding means for said screw operated by the weight of the landing gear to release the screw retarding means, and operated by the impact of the gear in landing to efiect action upon the screw 40. The combination with a 'retractable landing gear for airplanes, of a revoluble adjusting screw therefor having an acute pitch angle whereby the screw is revoluble in either direction under influence ofpitch of the pressure, and retarding means efiected by I signature 7 ll/llLTON GJBAUMANN 

